The goal of this study is to develop laboratory models to assess the possible role of Chlamydia in human infertility. The general approach will involve studies on the effects of active chlamydial infection or Chlamydia-induced damage on guinea pig and mouse fallopian tube function and intrauterine events. Thus, we will attempt to develop experimental models for acute salpingitis and its chronic sequelae. In addition, we will attempt to study infection of fertilized mouse ova and trophoblast outgrowths and the effects of in vivo and in vitro chlamydial infection on implantation of these ova.